1. Field of the Invention
The present invention relates to an injection/compression molding method, a die for injection/compression molding and an injection/compression molding machine suitable for forming precision injection moldings, such as half cases of tape cassettes, substrates for optical disks and optical lenses.
2 Description of the Related Art
An injection/compression molding method employs, in combination, the rapid charging function of an injection molding process and the uniform compression function of a compression molding process. The fundamental principle of injection/compression molding comprises injecting a resin in a slightly expanded cavity formed in a die, and compressing the die to reduce the volume of the cavity by a decrement corresponding to a reduction in the volume of the resin injected into the cavity resulting from liquid shrinkage on cooling to form a molding in desired dimensions.
Conventional injection/compression molding methods are classified roughly into two systems.